In U.S. Pat. No. 4,658,259, a current-fed antenna is disclosed for mounting on a glass plate with a radiator extending from one side of the glass plate and with the electrical wire extending from the opposite side of the glass plate whereby energy is transformed through the glass plate and the drilling of a hole for coupling the radiator to the electrical wiring is unnecessary. On occasion it is desirable to have an antenna, useful with a cellular telephone in a motor vehicle, that is portable so that it may be easily and rapidly mounted and dismounted from the window of the vehicle.
Certain prior art portable antennas have been found to have various undesirable qualities. For example, one prior art portable antenna used with motor vehicles requires the electrical cable to be extended from the inside of the vehicle to the outside of the window to which the antenna is connected. Another prior art motor vehicle antenna is voltage-fed which often creates problems when contaminants such as dirt and salt are introduced on the window surface and mixed with rain and snow, degrading the performance of the antenna. In addition, a voltage-fed antenna requires an LC resonant circuit which inherently has some loss, and the loss increases as the circuit becomes detuned.
It is, therefore, an object of the present invention to provide an antenna that is portable and alleviates many of the problems concomitant with prior art antennas.
Another object of the present invention is to provide an antenna that is simple in construction and efficient to manufacture.
Other objects and advantages of the present invention will become apparent as the description proceeds.